Offset rotary action sprinklers are generally used as agricultural irrigation sprinklers but because of their desirable performance at low to medium pressures they are becoming more commonly seen in domestic applications for watering smaller areas such as lawns, gardens and plant nurseries etc.
A feature of the operation of an offset rotary action sprinkler is that it has only one moving part, which is a gyrating deflector. The deflector has an annular member or ‘rolling ring’ held in place between two opposed surfaces provided around a threaded spout to which it is movably connected. The deflector also includes a set of offset radial deflector surfaces or ‘spray grooves’ connected to the rolling ring. The deflector is caused to roll, tilt and rotate, by the action of a water jet directed onto an apex of the spray grooves from a nozzle in the threaded spout. The spray grooves redirect the water jet from an axial trajectory to a radial (outwardly directed) trajectory. The grooves are typically located in or on a surface of a ‘spray cone’ which is connected directly to the rolling ring by posts which are located between the offset radial spray grooves, allowing the deflected water jet to exit the sprinkler fitting unimpeded. As the spray cone rotates, the water jet is deflected by different spray grooves, which break the water jet into ‘slugs’ and distribute the slugs of water radially. Offset rotary action sprinklers operate at varying pressures and flow rates to achieve different water distribution diameters and application rates appropriate to the application to which they are particularly targeted (e.g. agricultural or domestic applications). However, common to the design of all prior offset rotary action sprinklers is the manner of assembly, in which the threaded spout and deflector are each in turn made of at least two components assembled in a sequence that permits connection of the deflector to the threaded spout.
The threaded spout comprises the nozzle and an interconnecting thread provided to screw the threaded spout to a sprinkler base or pipeline water source. This threaded spout also includes a pair of opposed surfaces which are normal to the axis of the threaded spout and which retain the rolling ring of the deflector connected to the threaded spout and restrain the motion of the deflector. The two components of the threaded spout each provide one of the pair of opposed surfaces such that the two parts may be assembled to place the two opposed surfaces on opposite sides of the rolling ring, to thereby loosely hold the rolling ring located about the nozzle. The spray cone is then mounted on the rolling ring.
Thus to make a prior art offset rotary action sprinkler, requires the assembly of the two parts, each of which comprises multiple components, to enable the retention of the deflector of the sprinkler fitting within the confinement of the opposed faces of the threaded spout and to permit the rolling, tilting, rotating, or ‘gyrating’ action of its operation.
Two methods are commonly used to retain the deflector in position. One method involves having a removable nozzle component or nozzle retention component screwed to the top section of the threaded spout of the sprinkler fitting. The removable nozzle or nozzle retention component has a collar having an outer diameter larger than an opening in the annular rolling ring of the deflector. With the nozzle component or nozzle retention component removed, the annular rolling ring easily fits over the shank of the threaded spout. The nozzle component or nozzle retention component is then screwed down into position in the threaded spout to retain the deflector.
The other prior art method of assembling the deflector to the threaded spout involves placing the annular rolling ring over the shank of the threaded spout and pressing a flexible collar over the nozzle to retain the deflector.
In each case assembly of these prior art sprinklers requires the threaded spout to be made from two or more components whereby a rolling ring component is fitted over the spout and a retention component is then attached. Similarly the deflector comprises a rolling ring and a spray cone, which must be assembled together after the rolling ring is retained on the threaded spout.